This invention relates to a semiconductor laser device having a low threshold current and excellent temperature characteristics.
It is well known that several structures of semiconductor lasers have been produced in which the threshold current is decreased. Among them a laser structure known as the so-called transverse junction stripe (abbreviated as "TJS") laser is particularly excellent. That TJS laser oscillates in the single mode and the characteristics thereof are described in detail, for example, in an H. Namizaki article entitled "Transverse-Junction-Stripe Lasers with a GaAs p-n Homojunction," IEEE Fournal of Quantum Electronics, QE-11, Nov. 8, 1975, pages 427-431. However, the TJS laser has been disadvantageous in that a leakage current, not contributing to the laser oscillation, increases with an increase in current density and therefore a temperature rise is attended with a rapid increase in threshold current until the laser oscillation is ceased due to heat generated therein.
Accordingly it is an object of the present invention to provide a new and improved semiconductor laser device having an extremely low leakage current.
It is another object of the present invention to provide a new semiconductor laser device which is improved in the temperature dependency of the leakage current.
It is still another object of the present invention to provide a new and improved semiconductor laser device having a low threshold current and still a reduced rate of temperature change thereof.